Commercial aircraft set up for the transportation of passengers typically include rows of seats along the length of the aircraft cabin. Because the primary purpose of this type of commercial aircraft is to transport passengers, the aircraft cabin is usually set up to maximize the number of seats in the cabin. However, increasing the number of seated passengers in the aircraft cabin also increases the potential for the transfer of microorganisms or other air suspend impurities between the passengers in the aircraft cabin.
The potential problem of airborne disease or other air suspended impurities in the cabin of an aircraft is mitigated by dilution ventilation. The removal of microbials from the breathing space of an aircraft cabin reduces the risk of airborne infection. Current disease models suggest that some benefit is obtained by increasing the flow of pathogen free air to the aircraft cabin. Current ventilation air distribution systems provide between 15 and 25 cfm per passenger in economy seating. The ventilation air distribution systems are flowing at the maximum capacity of the ducting of the system and the system fans. Thus, the limited capacity of current air distribution systems in passenger aircraft is a primary problem in reducing the risk of airborne infection.
One solution is to reduce the passenger count, thereby increasing the ventilation flow per person. However, reducing the passenger count is not a popular solution because it drives up the cost of the airline ticket proportionately, wastes fuel, and causes flight delays through the increased aircraft traffic resulting from reducing the number of passengers in each aircraft.
Ultraviolet light sterilizers irradiating ventilation air are very effective in providing pathogen free ventilation air. However, exposing the passengers to the radiation of ultraviolet light is not acceptable.
Filter material, for example felt, could be added to the air ventilation distribution system to remove air suspended impurities. However, in warm, high humidity environments the filter material would absorb moisture from the cool ventilation air, thereby becoming a source of bacterial growth. Additionally, the wet filter material could present the problem of condensation dripping on passengers during open door loading in the humid environment.